The compound 2-[(2-chlorophenyl)methyl]-4,4-dimethyl-3-isoxazolidinone, hereinafter referred to by the common name "clomazone", is a potent herbicide as evidenced by its ability to control, for full growing seasons and at low application rates in soybean stands, a broad spectrum of grasses and broadleaf weeds that compete with soybeans. However, clomazone is phytotoxic to other crops when applied at rates effective to control undesired vegetation, such contact resulting from drift to adjacent fields planted with low tolerance crops or from carryover when soybean fields treated with clomazone are rotated to a crop sensitive to clomazone. Typical of the crops sensitive to herbicidal rates of application of clomazone are cotton, wheat, corn and barley.
Although clomazone can be, and is, sold with suitable instructions to prevent exposure to sensitive crops, it will be evident that measures that will increase the tolerance of desirable plants to clomazone without substantial diminution of herbicidal efficacy against weeds, will greatly expand the usefulness of clomazone and ultimately result in lower cost.
In this specification the term "crops" includes not only agronomic crops but plants of all kinds, particularly cereal and non-cereal grassy crops, such as corn, wheat, oats, barley, rice, cotton, sorghum, sugar cane, sugar beets and peanuts, including hybrids thereof.